The lithium ion rechargeable battery has been in widespread use as a small and light-weight rechargeable battery having a high capacity and high voltage and is suitable for use in portable equipment such as a cellular phone, a video camera, and so forth. Further, a lithium ion rechargeable battery having a high-output has lately come into widespread use as a power supply for an electric power tool requiring a large amount of power.
As there has been seen no sign of a slowdown in the trend for portable equipment towards further miniaturization, higher performance and higher function, so miniaturization•lighter weight, and higher capacity are required of the lithium ion rechargeable battery.
While attempts have been made to achieve a higher performance with respect to each of the components of the lithium ion rechargeable battery and material thereof, particular importance is attached to a higher density•higher capacity of a negative electrode material among others, as a determinant of battery performance, so that spheroidizing of a graphite particle has been proposed.    Patent Document 1 JP 2983003B    Patent Document 2 JP 3588354B    Patent Document 3 JP 3716830B    Patent Document 4 JP 3716818B    Patent Document 5 JP 11-73963A